Sulky

ABSTRACT

Sulky comprising two wheels individually fastened along the same rotational axis, to a common structure provided with a driver&#39;s seat (4) and shafts (3) leading towards the draught animal. The sulky (1) consists of a construction kit comprising a plurality of substantially flat elements (2, 3, 4, 5, 6) adapted to be assembled by the end user by means of ordinary hand tools. Two of these parts are end frames (5) adapted for fastening of a wheel (2), a shaft (3), and the crossbar (6) in the same vertical plane.

FIELD OF THE INVENTION

The present invention relates to a sulky comprising two wheels,individually fastened, but located along the same rotational axis, to acommon frame provided with a driver's seat and shafts leading towardsthe draught animal.

DESCRIPTION OF RELEVANT ART

Sulkies of this type are used for trotting races and the most importantrequirements are that they have a lightweight construction, that theyare easy-running, and that they are strongly built to endure thespecific strain during excercise and competitions.

To obtain constructions of a sufficiently stiff and stable structure andat the same time of lowest possible weight, sulkies so far have beenmanufactured as welded steel constructions as this has led to the mostlightweight construction combined with sufficient strength.

Certainly there have earlier been attempts to build sulkies ofaluminium, however such sulkies have got a rather bad reputation due topoor strength qualities.

A conventional sulky has its shafts fastened approximately 10 cms insideof the wheels. This fact leads to a construction well adapted for weldedsteel pipes, but it is unsuitable when light metals are used because theconstruction then requires welding. This is probably the reason whyearlier attempts using aluminium have failed, as the design then hasbeen similar to the conventional steel constructions requiring a weldingprocess. It is a fact that aluminium and other light metals aredifficult to weld, in particular weaknesses in the metal can not beallowed at, or close to, the welding points.

Storing and transportation of conventional sulkies has led todifficulties due to the sulkies having an awkward shape. Themanufacturing process has also been expensive and much handwork has beenrequired. Sulkies having even less weight have always been desirable,even if specialists in this field of technique have been convinced thatstill lighter sulkies could not be manufactured without a correspondingstrength reduction.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a new sulkyconstruction having such a design that it may be manufactured of lightmetal and other lightweight and yet durable materials.

A further object of the present invention is to provide a sulky whichmay be assembled easily by a user himself, from substantially flatelements requiring only a small space during storage and transportation,said elements being easily dispatched in a flat package.

Still a further object of the present invention is to build up a sulkyfrom inexpensive semi-produced components as casted elements andextruded profiles.

Still a further object of the present invention is to provide a sulkyhaving a stable construction as the shafts as well as the crossbartransfer substantially all the load to the wheel planes only.

Finally it may be mentioned that an object of the present invention isto provide a sulky which easily may be assembled by the user himself bymeans of ordinary hand tool, and where all the connections becomesecure, without any play, even if the single components are producedwith ordinary manufacturing tolerances.

It should be mentioned that the new sulky construction having shaftsfastened to the frame in the planes of the wheels results in thepossibility of avoiding the traditional manual manufacturing processincluding welding of each individual sulky and instead using casting andmass production with corresponding low expenses. By changing to acasting process many of the details required in connection with thewheel suspension, the fastening of the shafts and the crossbar to theframe, may be integrated in the casting process without any additionalexpenditures. A design of the end frames as stated in connection withthe present invention is also required to obtain a structure being wellsuited for box packaging and do-it-yourself kits based on simplethreaded connections.

There is also obtained a weight reduction of approximately 40% for thecomplete sulky which has a total weight of approximately 18 kg in aready-to-use state.

Finally it should be mentioned that a sulky according to the presentinvention in particular is designed to be colored by applying colortapes in all recesses of the profiles, a solution which leads to aninexpensive and individual color display system important for the endusers.

BRIEF DESCRIPTION OF THE DRAWINGS

To give a clear understanding of the present invention reference is madeto the detailed description of an embodiment given below, and to theaccompanying drawings in which:

FIG. 1 illustrates a side view of a sulky according to the presentinvention,

FIG. 2 illustrates a top view of a sulky according to FIG. 1,

FIG. 3 illustrates a cross section of the crossbar at the connection toan end frame,

FIGS. 4A-4C show an end frame in more detail, and

FIG. 5 shows how a dismantled sulky may be arranged in a flat package.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In all of the Figures the same reference numbers are used for componentshaving the same function, when appropriate.

In FIG. 1 the sulky 1 is shown in a side view, and it may be seen thatboth the wheel 2 and the shaft 3 are mounted to the end frame 5.

When FIG. 2, which shows the same sulky as in FIG. 1, but now seen fromabove, is compared with FIG. 1, where the same reference numbers areused, it may be seen that the driver's seat 4 is arranged centrally onthe crossbar 6 which is fastened to the mounting bushings 7 in the endframes 5.

In FIG. 2 the foot treads 8 fastened to the shafts 3 also are shown, andFIG. 2 in particular shows how the end frames are shaped so that thewheel-fastening, shaft-fastening and crossbar-fastening devices all arearranged in the same vertical plane. This is important to obtain a bestpossible load situation.

As shown in FIGS. 1 and 2 the end frames 5 are arranged symmetricallyrelated to the plane of the wheels 2. This leads to a stableconstruction of the sulky, but differs from conventional solutions. Itmay also be understood from FIGS. 1 and 2 that the crossbar 6 is adaptedto the mounting bushings 7 and may be fastened thereto. An example ofthe assembly of those joints is described in more detail below. Thedetails of these joints are important to obtain a stable and rigid framewhich may resist the strain occuring during use, and this may beobtained without demanding requirements on the materials in thesecomponents or to the manufacturing tolerances of same. According to apreferred embodiment of the present invention the end frames 5,preferably of aluminium or a similar light metal, are casted, e.g. bymeans of a chill-casting or press-casting process using a light metal,or alternatively by producing the frames of reinforced plastics whilethe crossbar 6 may be manufactured of extruded aluminium or a similarlight metal. Despite the inexpensive process and easily workablematerials the geometric design leads to a stable and reliableconstruction.

The wheels may be fastened to a fork section 9 of the end frames 5 bymeans of conventional fastening technique, and in a similar manner theshafts 3, which may be made of light metal or plastics reinforced e.g.by carbon fibers, may be fastened to the end frames 5 by means ofhorizontally arranged fastening bolts 16 and further fastening screws 17arranged in corresponding holes in the shaft 3. Thereby a fastening ofthe shaft so as to be adjustable in a longitudinal direction isobtained.

Finally it may be mentioned that the driver's seat 4 is fastened to thecrossbar 6 by means of extruded brackets 12 which, if required, may beclamped thereto by means of conventional clamping devices comprisingscrews or bolts.

The crossbar 6 and the fastening of the same in one of the mountingbushings 7, is shown in more detail at the cross section illustrated inFIG. 3. The crossbar may be designed as an extruded aluminium profile 13having a closed cross section with internal extending protrusions 14 and15. In addition there are strengthening elements 18, 19 adapted to fitin with friction between the protrusions 14 and 15. Centrally in thesestrengthening elements threaded holes 20 and 21 are arranged, and thestrengthening elements may be shifted along the aluminum profile 13 to asuitable place so that the threaded holes 20 and 21 coincide with theassembling recesses in the profile 13 and the mounting bushing 7. It maybe noted that the strengthening elements 18, 19, arranged ondiametrically and opposite faces of the aluminium profile 13, may becombined in one common integrated part as they may be designed, forexample as a U-shaped or O-shaped bracket which may be shifted withinthe track made up of the protrusions 14 and 15. The material of thestrengthening elements 18 and 19 may be stainless steel or a similarmaterial having a higher rigidity than the material of the extrudedprofile 13.

In FIG. 3 one of the mounting bushings 7 is shown together with throughscrews 22 adapted for fastening the crossbar 6 to the mounting bushing7. In this connection it is important that the manufacturing tolerancesduring extruding and casting allow easy introduction of the extrudedprofile 13 in the mounting bushing 7 with suitable play, however, insuch a manner that the materials have a flexibility and deformabilityadapted so that when the screws 22 are tightened, the extruded profileand mounting bushing 7 will be pulled together by the strengtheningelements 18 and 19 respectively, and possibly between oppositelyarranged, external strengthening washers 23. After this tighteningprocess the surfaces of the crossbar 6 and the mounting bushing 7 havebeen somewhat deformed, and therefore an exact adaptation is obtained.It should also be noted that outside the mounting bushing 7 there mayalso be placed strengthening washers 23, possibly counter bored in thebushing wall so that the material of the bushing 7 and the material ofthe extruded profile 13 are squeezed between element 19 and a washer ofnon-corrosive material 23, respectively, and are forcibly pressedtowards the rigid bushing 7. Even if the manufacturing tolerances of theextruded profile and the bushing initially left some mutual play, thetightening of the bolt 22 deforms the material so that a close anddurable connection is obtained. This connection method ensures a stableand reliable assembly using very simple means.

In FIGS. 4A-4C still more details of the end frame 5 are shown. Here thecross sections of the different parts of the frame also are illustrated.It may in particular be mentioned that the mounting bushing 7 has across section that with a certain play is adapted to the externalsection of the extruded aluminium profile which constitutes the crossbar6 and is shown in FIG. 3. The loads are evenly distributed due to thesymmetrical design of the end frames relative to the wheel planes, andthis fact also contributes to a reliable solution in spite of the simplemounting process. The end frame has such a design that it may be cast ina tool comprising only one core and two side walls. The core may bepulled out vertically in a downward direction on the drawing, while allthe side elements are bent out to slip the casted element, and theinside and outside of the mounting bushing 7 are formed in contact withthe side elements.

The right and the left end frames are preferably casted in the same tooland are therefore quite identical when casted. The tool expensestherefore are reduced and also the storing charges as the number ofspare parts also are reduced. In the shown embodiment the external partof the mounting bushing 7 is removed from opposite sides of the endframes before the assembly process, and the resulting holes are coveredby caps. However, the invention comprises embodiments where the two endframes are maintained identical also after assembly.

If the qualities of the material and the cross section so allow, thecentral parts of the crossbar, i.e. the region where the bending momentreaches its maximum value during use, may be reinforced by introducing asquare profile between the protrusions 14 and 15.

An important advantage of the present invention is that the completesulky may be packed into a flat box for storing and transportation todistributers. The user may then buy the sulky as a construction kit andmount the parts himself in a quarter of an hour and then obtain areliable and professional sulky having a lower total weight but withuser qualities equal to those of traditional sulkies. It should also bementioned that the end frames 5 are identical during production and thusfreely may be used on the right or the left side of the sulky. Theprotruding part of the mounting bushing 7 may then be removed by asimple cutting process before assembly.

We claim:
 1. A sulky comprising:two wheels having a substantially flatconfiguration; a driver seat having a substantially flat configurationconnected to a chassis; said chassis including a plurality ofsubstantially flat elements detachably assembled together so as to beeasily removable from each other by hand tools, the plurality ofsubstantially flat elements including a crossbar, a pair of shafts, anda pair of end frames, said end frames each having a substantiallytriangular shape with three corners and having mounting structuresdetachably connecting the shafts and crossbar to the end frames with thecrossbar extending between the end frames and one of the shaftsextending away from each respective end frame, said end frames furtherbeing detachably mounted to, respectively, the two wheels such that theconnections between one of said end frames and one of said shafts and anend of the crossbar are disposed, at longitudinally spaced locations, ina substantially common vertical plane extending substantiallylongitudinally to the sulky and through substantially the center of thewheel; whereby a user may assemble and disassemble the sulky in a simplemanner using ordinary hand tools.
 2. A sulky according to claim 1,wherein each of said frames is a single piece element.
 3. A sulkyaccording to claim 1, wherein each of said frames is a single piececasting.
 4. A sulky according to claim 1, wherein said connectionsbetween said one of said end frames and said one of said wheels, saidone of said shafts, and said end of the crossbar are proximaterespective ones of said three corners of said substantially triangularshape of said one of said end frames.
 5. A sulky according to claim 1,wherein said frames are symmetrical around center planes of said wheels.6. A sulky according to claim 1, wherein center planes of said wheelsare substantially the same as said common vertical planes.
 7. A sulkyaccording to claim 1, wherein said end frames each include a forksection surrounding said wheels and connected to said wheels at oppositesides thereof.
 8. A sulky comprising:two wheels having a substantiallyflat configuration; a driver seat having a substantially flatconfiguration connected to a chassis; said chassis including a pluralityof substantially flat elements detachably assembled together so as to beeasily removable from each other by hand tools, the plurality ofsubstantially flat elements including a crossbar, a pair of shafts, anda pair of end frames, said end frames having mounting structuresdetachably connecting the shafts and crossbar to the end frames with thecrossbar extending between the end frames and one of the shaftsextending away from each respective end frame, said end frames furtherbeing detachably mounted to, respectively, the two wheels such that theconnections between one of said end frames and one of said shafts and anend of the crossbar are disposed, at longitudinally spaced locations, ina substantially common vertical plane extending substantiallylongitudinally to the sulky and through substantially the center of thewheel; whereby a user may assemble and disassemble the sulky in a simplemanner using ordinary hand tools; and wherein each of said end frameshas a substantially triangular shape with three corners, a first cornerbeing provided with two forked arms detachably mounted to an axle of oneof said wheels; a second corner being provided with a mounting bushingarranged substantially parallel to the wheel axle and detachablyreceiving an end of the crossbar, and the third corner being providedwith an assembly opening substantially in the same plane as the wheeland receiving one of said shafts.
 9. A sulky according to claim 8wherein said crossbar includes an extruded hollow profile, with an outerdimension and shape which with a certain play fits into the mountingbushings, the hollow profile being provided with internal fasteningmeans for receiving at least one strengthening element provided with aninternal, threaded hole which is adapted to correspond with holesformed, respectively, in the mounting bushing and the hollow profile ofthe crossbar.
 10. A sulky according to claim 9, further including twostrengthening elements each comprising a one-piece element provided witha threaded boring positioned diametrically opposite holes in themounting bushing and in the hollow profile.
 11. A sulky according toclaim 10, wherein a strengthening washer is arranged on an outer side ofthe mounting bushing and has unthreaded holes corresponding to saidholes in the bushing and hollow profile.
 12. A sulky according to claim10, wherein the material for the end frames and the crossbar is a lightmetal which may be deformed by strain caused by force applied byordinary hand tools, while the strengthening elements are formed of amore rigid material.
 13. A sulky according to claim 9, wherein thematerial for the end frames and the crossbar is a light metal which maybe deformed by strain caused by force applied by ordinary hand tools,while the strengthening element is formed of a more rigid material. 14.A sulky according to claim 9, wherein a strengthening washer is arrangedon an outer side of the mounting bushing and has unthreaded holescorresponding to said holes in the bushing and hollow profile.
 15. Asulky according to claim 9, wherein the assembly opening for receivingthe shaft is provided with horizontal tightening screws and a verticallyarranged set screw which penetrate both the wall of the assembly openingand the shaft mounted therein.
 16. A sulky according to claim 8 whereinthe assembly opening for receiving the shaft is provided with horizontaltightening screws and a vertically arranged set screw which penetrateboth the wall of the assembly opening and the shaft mounted therein. 17.A sulky according to claim 8, wherein the two end frames when assembledhave a completely identical geometric shape.
 18. A sulky according toclaim 17, wherein the end frames are manufactured so that theirgeometric shapes are identical, and during assembly the end frames areable to be modified by removing an outer portion of the mounting bushingfrom opposite sides of the respective end frames to form a right andleft end frame which when assembled will be symmetric about a centralplane of the sulky.
 19. A kit for constructing a sulky from a pluralityof components which may be assembled by hand tools to form the sulky,the kit comprising:two wheels having a substantially flat configuration;a driver seat having a substantially flat configuration; a crossbar; apair of shafts; and a pair of end frames, each of the end frames havinga generally triangular shape including a first corner provided with twoforked arms for detachably mounting an axle of one of said wheels, asecond corner provided with a mounting bushing for detachably receivingan end of the crossbar, and a third corner provided with an assemblyopening for receiving one of said shafts; whereby upon assembly of thesulky the crossbar extends between the end frames and one of the shaftsextends away from a respective end frame, and the connections betweenone of the end frames and one of the shafts and an end of the crossbarare disposed in a substantially common vertical plane extendingsubstantially longitudinally to the sulky and through substantially thecenter of the wheel.